Submersible electric motor



June 10, 1952 s. A. SMITH 2,600,277

SUBMERSIBLE ELEGTRIC MOTOR June 10, 1952 s. A. sMlTH 2,600,277

SUBMERSIBLE ELECTRIC MOTOR Filed Jan. 13, 1951 5 Sheets-Sheet 2 FIGZ.

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June l0, 1952 -s. A. sM|TH 2,600,277

SUBMERSIBLE ELECTRIC MOTOR Filed Jan. 15, 1951 s sheets-sheer s IZI i I wf/v70@ e Tam af/MM fm1 7 @d Patented June 10, f1952 land, assignortoJames Beresfordia SonrLim.- ited, Birmingham, England, a...=corporation ol' Great Britain .ApplicationJanuary 13, 1951, SeriallNo. rZIlSgSBil -In l.Great YBritain yMay-.6; 19.5.0,

6' Claims. l'.

This invention .has reference toimprovements relating. to .submersible electric motors Submersiblev electric motors generally arev of thev squirrel cage type and'in. thelarger sizes vof such.motors.particularly, some difficulty is experienced in obtaining. efcient cooling, andA the present invention .has for its. object to make pro-y vision for ensuring., the adequate cooling of submersible electric motors ofthe squirrelcage type o-f all sizesin a manner -whichis capable vof being adapted to submersible electric motors of the squirrel cage `type of existing design without necessitating any material .constructionalalteration thereto.

Accordingly the .invention consists .of .animproved submersible electric motor. ofthesquirrel cagetypein which a` surface .boundingfthe space between the rotor. shaft andthe inner. periphery ofthe rotorcore isgrooved .spirallyand in which the outer periphery. of the rotor. core is.grooved spirally but with the grooving of. opposite hand to the Agroovingfof thesurface aforesaidand in which the groovings.. are open to the spaces through. which .the coolant is. .to becirculated whereby whenthemotor isinloperation the rotation .of the rotor. induces acirculationof l coolant inthe groovings .witlrthe .direction of circulation induced .inr thegrooi/'ingl in avsurfacebounding the spacebetween-the rotor shaft andthelinner periphery of therotor core. opposite to the directionof .circulation inducedin the grooving inthe outer .peripherysof .the rotor core,y thereby occasioningand ensuring. a. continuous Ycirculation, of coolant through the space/between therotorfshaft and the inner periphery ofv .the rotor coreand v through the.Y space between `the-rotor and the stator.

An embodiment ofl they invention, willv new be described-withpartieulanreferento ,the accom- -Panyingz drawings which illus-trate thefinvention in its application.to.a:submersible-electric motor of thev squirrelcage typeas incorporated in the lwell .known Beresford submersible; electrically "driven .pump.

.In thefdrawings:

.Figure 'l is a conventionalised "representation partly in elevation Vandpartly"inyvertical section 'ofjithe motor section of a` Beresford submersible electrically drivenpump incorporatingtheinvention.`

.Figure 2Aisa view .partly in elevation and4 partly in section. and on an.. enlarged. scaleof the relelvanty part .of the .actual constructional 'form'r of the` electric motor section .of a Beresfordv sub mersible. electrically.. driven. pump. incorporating the: invention.

Figure 3 .is a sideelev-ation of the rotor utilised in the .electric motor, illustrated in Figures. 1 and 2.

Figures is `a side elevation` of -the rotor shaft utilised; in the construction. ofV the .rotor illustrated in Figure 3.

Figure-5.15 a cross section of .Figure .3. -takenon the. plan-e indicatedby the line 5-5in Figure 3.`

AIn* the. drawings- .like numerals of reference indicate similar parts in the several views.

As thergeneral arrangement, construction and mannerE .or operation of the Beresford .submersibleelectrically driven .pump is. well known it will suiilce for present 'purposes .to State that .the :motor section .of the. saidpumpas illustrated in conventionalised form in Figure 1 incorporates:

(a)y An fouter casing` III 'fo'ffa non-ferrous metal, (b) An relectric motor of rthe squirrelcage type having (i) A stator Llwhich is associated in xed relationship .Withthe `casing I0,

(it) Arotor shaft I2, the upper end Vportion of .which is rotatably. mountedin .bearings l5., whilst. rthe, lower end portion isrotatably .mountedinbearings .I 6, and

(iiz'lA, laminated. rotor, `core I3 which. is mounted onand keyed .to the-rotor shaft .I.2

.(c) A reservoir '|11 for `a lubricantand coolant consisting..- of .ran emulsion 0f' oil and water, securedv to the bottom closure member IOI 'for the-outer casing I 0,

(d) A closuremember I 02v for the upper fend of .theouter; casingl which is surmounted -by a casingl -fwhichalso surrounds-- the upper end portionof. the .rotor` shaft I2,

(e) A; sleeve .I Srwhichsurrounds the core I3 and screens the stator-1 I.,

(f) Passagesand spaces .for placing. thespaces .surrounding 'the-rotor shaf t I2 .and .rotor core I3 in communicationwithrthe reservoirv I1l and wthjthe interior of thecasing I8.

According-tof theillustrated veinbodimenty ofthe invention the rotor shaft I2.r is provided with a right, handA Spiral groove I2I off semi-circular shape in cross section the lower end of which opens into the. space 2Il;I surrounding-the lower endV portion ofthe-rotor shaft I 2 l whilsttheother .endof the .saidfxgroovesltl opensintothe space .202 surrounding the- .upper end :portion of. the

rotor shaft I2, said groove |2| also being open throughout its length to the space 203 between the outer periphery of the rotor shaft |2 and the inner periphery of the rotor core I3. The right hand formation of the groove |2| ensures that when the rotor shaft I2 is rotated in a clockwise direction looking from the top, circulation of the coolant is induced through the space 203 between the outer periphery of the rotor shaft |2 and the inner periphery of the rotor core I3 in an upwards direction.

The outer periphery of the rotor core I3 is provided with a left hand spiral groove |3| of rectangular shape in cross section which is open throughout its length to the space 204 surrounding the outer periphery of the rotor core I3.

The turns of the groove |2| in the rotor shaft l2 are alternated with the turns of the groove |3| in the outer periphery of the rotor core I3.

The left hand formation of the spiral groove |3| in the outer periphery of the rotor core |3 ensures that when the rotor core is rotated in a clockwise direction looking from the top circulation of coolant is induced through the space 204.

Thus when the motor is in operation there is a continuous circulation of the coolant through the spaces 203 and 204.

If preferred the outer periphery of the rotor shaft I2 and the cuter periphery of the rotor core I3 may be provided with more than one groove |2|, 13|.

Moreover if preferred instead of grooving the outer periphery of the rotor shaft I2 the relevant grooving may be provided in the inner periphery of the rotor core I3.

The rotor shaft I2 is provided with impellers |22, |23, |24 which are turnable therewith, the impeller |22 discharging directly onto the wall of the sleeve I9 slightly above the place of discharge from the groove |2| which also is directed onto the wall of the sleeve I9 (see Figures 1 and 2).

The suction of the impeller |24 is assisted by holes 2|I in a stationary part 2I.

It should be pointed out that on the assembly of a motor the whole of the interior of the outer casing I is filled with coolant as well as the reservoir I'I and that the coolant which fills the space 205 surrounding the upper portion of the rotor shaft |2 and the space 206 surrounding the sleeve I| which carries the bearings |5 for the upper end of the rotor shaft I2, is caused to circulate downwardly through the space 205 and upwardly through the space 2516 by the action of the impeller |22 and the reaction due to the said impeller |22 and the groove |2| discharging coolant directly onto the wall of the sleeve I9 in close proximity.

The manner of circulation of the coolant in the illustrated embodiment of the invention is indicated by the arrows in Figure 1.

It will be appreciated that the invention ensures an eiiicient and continuous circulation of coolant in the space 203 between the rotor shaft I2 and the inner periphery of the rotor core |3 and in the space 204 surrounding the outerperiphery of the rotor core I3 thereby ensuring more efficient cooling than has been attained heretofore.

Furthermore it will be appreciated that the invention is not limited to submersible squirrel cage type electric motors as used in the Beresford submersible electrically driven pump but 4 may be applied to squirrel cage type submersible electric motors of other constructions.

I claim:

l. A submersible electric motor of the squirrel cage type incorporating a liquid tight casing which is required to be filled with a liquid coolant and a rotor comprising a core and a shaft which are enclosed within said casing and which has Spiral grOoVng in the outer periphery of the core of the said rotor and which has spiral grooving in a surface bounding the space between the inner periphery of the said core and the rotor shaft on which said core is mounted, said groovings being of opposite hand with the inlet of the inner'grooving and the outlet of the outer grooving opening into the same portion of the liquid filled casing and with the outlet of the inner grooving discharging on to the bounding surface of the casing in proximity to the inlet of the outer grooving whereby, when the motor is in operation, the rotation of the rotor induces a circulation of coolant in the groovings with the direction of circulation induced in the inner grooving opposite to the direction of circulation induced by the outer grooving thereby occasioning and ensuring a continuous circulation through and around the rotor core.

2. A submersible electric motor of the squirrel cage type incorporating a liquid tight casing which is required to be filled with a liquid coolant, a rotor comprising a core and a shaft which are enclosed within said casing and which has spiral grooving in the outer periphery of the core of said rotor and which has spiral grooving in a surface bounding the space between the inner periphery of the said core and the rotor shaft on which said core is mounted, said groovings being of opposite hand with the inlet of the inner grooving and the outlet of the outer grooving opening into the same portion of the liquid filled casing and with the outlet of the inner grooving discharging on to the bounding surface of the casing in proximity to the inlet of the outer grooving and inner and outer passages for circulation of coolant in a part of the casing not occupied by the rotor core with the outlet for the said inner passage adapted to discharge on to the bounding surface of the casing in proximity to the place of discharge of the outlet of the inner grooving aforesaid so that when the motor is in operation the rotation of the rotor induces circulation of coolant in the groovings with the direction of circulation induced in the inner grooving opposite to the direction of circulation induced by the outer grooving thereby occasioning and ensuring a continuous circulation through and around the rotor core whilst the reaction due to the two streams of discharge from the outlet of the inner grooving and the outlet of the inner passage occasions a separate circulation of coolant through the inner and outer passages aforesaid.

3. A submersible electric motor of the squirrel cage type incorporating a liquid tight casing which is required to be filled with a liquid coolant, a rotor comprising a core and a shaft which are enclosed within said casing and which has spiral grooving in the outer periphery of the core of the said rotor and which has spiral grooving in a surface bounding the space between the inner periphery of the said core and the rotor shaft on which said core is mounted, said groovings being of opposite hand with the inlet of the inner grooving and the outlet of the outer grooving opening into the same portion of the liquid lled casing and with the outlet of the inner grooving discharging on to the boundingsurface of the casing in proximity to the inlet of the outer groovng whereby when the motor is in operation the rotation of the rotor induces a circulation of coolant in the groovings with the direction of circulation induced in the inner grooving opposite to the direction of circulation induced by the outer grooving thereby occasioning and ensuring a continuous circulation through and around the rotor core and means for assisting in the circulation of coolant to the inlet of the inner grooving.

4. A submersible motor of the squirrel cage type incorporating` a liquid tight casing which is required to be filled with a liquid coolant, a well in the lower portion of said casing, a rotor comprising a core and a rotor shaft which are enclosed within the intermediate portion of said casing and which has spiral grooving in the outer periphery of the core of the said rotor and which has spiral grooving in a surface bounding the space between the center periphery of the said core and the shaft on which the said core is mounted, said groovings being of opposite hand with the inlet of the inner grooving and the outlet of the outer grooving in communication with the well aforesaid and with the outlet of the inner grooving discharging on to the bounding surface of the casing in proximity to the inlet end of the outer grooving, inner and outer passages for circulation of coolant in the upper portion of the casing above the rotor core with the outlet for the inner passage adapted to discharge on to the bounding surface of the casing in proximity to the place of discharge of the outlet of the inner grooving, so that when the motor is in operation the rotation of the rotor induces circulation of coolant in the groovings with the direction of circulation induced in the inner grooving opposite to the direction of circulation induced in the outer grooving thereby occasioning and ensuring a continuous circulation through and around the rotor core whilst the reaction due to the two streams of discharge from the outlet of the inner grooving and the outlet of the inner passage occasions a separate circulation of coolant through the inner and outer passages aforesaid and means for assisting flow of coolant under pressure to the inlet of the inner grooving.

5, A submersible motor of the squirrel cage type incorporating a liquid tight casing which is required to be lled with a liquid coolant, a

well in the lower portion of said casing, a rotor comprising a core and a rotor shaft which are enclosed within the intermediate portion of said casing and which has spiral grooving in the outer periphery of the core of the said rotor and which has spiral grooving in a surface bounding the space between the center periphery of the said core and the shaft on which the said core is mounted, said groovings being of opposite hand with the inlet of the center grooving and the outlet of the outer grooving in communication with the well aforesaid and with the outlet of the inner grooving discharging on to the bounding surface of the casing in proximity to the c inlet of the outer grooving, inner and outer passages for circulation of coolant in the upper portion of the casing above the rotor core with the outlet for the inner passage adapted to discharge on to the bounding surface of the casing in proximity to the place of discharge of the outlet of the inner grooving, means for effecting discharge under pressure from the outlet of the inner passage aforesaid so that when the motor is in operation the rotation of the rotor induces a circulation of coolant in the groovings with the direction of circulation induced in the inner grooving opposite to the direction of circulation induced in the outer grooving thereby occasioning and ensuring a continuous circulation through and around the rotor core whilst the reaction due to the two streams of discharge from the outlet of the inner grooving and the outlet of the inner passage occasions a separate circulation of coolant through the inner and outer passages aforesaid and means for assisting in the circulation of coolant under pressure to the inner end of the inner groove.

6. Submersible electric motor according to claim 1 in which the turns of the inner grooving alternate with the turns of the outer grooving.

SIDNEY ARTHUR SMITH.

REFERENCES CITED The following references are of record in the nie of this patent:

UNITED STATES PATENTS Number Name Date 422,681 Wray Mar. 4, 1890 959,550 Kingsbury May 31, 1910 1,955,955 Fabrin Apr. 24, 1924 2,043,236 Conant June 9, 1936 2,353,336 Heintz et al July 11. 1944 

